1. Field of the Invention
This invention pertains to paper handling, and more particularly to apparatus that processes business forms.
2. Description of the Prior Art
A wide variety of machinery has been developed to handle printed forms on a commercial basis. For example, machines that fold sheets of paper into different configurations are well known and in widespread use. Such machines, usually called xe2x80x9cfoldersxe2x80x9d, are capable of creating C, V, Z, eccentric C, eccentric Z, and double parallel folds in paper sheets at high speeds.
It is also well known to seal the folded sheets each to itself. For that purpose, strips of adhesive are applied at desired locations on the sheets. The modern tendency is to use pressure sensitive adhesives. After a sheet with pressure sensitive adhesive strips has been folded, it is fed to a sealer machine. In the sealer machine, pressure is applied to the adhesive strips. The applied pressure activates the adhesive and causes the sheet to adhere to itself along the strips. Exemplary pressure sealer apparatus is shown in U.S. Pat. No. 5,772,841 assigned to Bescorp Inc. of Dover, N.H.
In the past, folders and pressure sealer machines were normally distinct and independent pieces of equipment. Although certain models of pressure sealers were especially compatible with certain models of folders, a folder-sealer machine installation usually required custom engineering to make the two machines work together properly. In addition, the prior individual folders and pressure sealers were relatively expensive. They were also bulky and heavy. Consequently, purchasing and installing prior folder and sealer machines was a costly and time consuming project.
Another major disadvantage of prior folder and sealer machines is that the forms were under little, if any, control as they passed from the folder to the sealer machine. Usually, the folded forms emerged from the folder onto a conveyor belt, which transported them to the sealer. While on the conveyor belt, friction was often the only means used to maintain the forms at the desired alignment necessary for proper input into the sealer. The result was that the forms could skew as they traveled to the sealer. Some conveyors had wheels that rode on top of the forms to help keep them properly aligned. The top wheels, however, did not completely prevent the forms from skewing. A skewed form would jam the sealer and cause a pile-up of forms upstream, which required unproductive down time to clear.
In addition to the mentioned problems pertaining to folder and sealer equipment as used together, there was a disadvantage of prior folders themselves. That disadvantage pertained to the mounting of the folding rollers in the machine frame. In many designs, the folding rollers, once installed, were very difficult to remove. Hence, replacing worn or damaged folding rollers was a time consuming chore.
Moore Business Forms, Inc. of Grand Island, N.Y., markets a compact folding and sealing mailing system under the trademark SpeediSealer. Although the Moore machine possesses several desirable features, there nevertheless is considerable room for further improvement to folding and sealing equipment.
In accordance with the present invention, a combination folder and sealer machine is provided that maintains continuous control over sheets processed by the machine. This is accomplished by apparatus that includes a fold nip and a seal nip that simultaneously grip each sheet while the sheets are being processed.
Unfolded sheets are stacked at a feeder station. The sheets are fed one at a time in a downstream direction to a folder station. The sheets pass through the rollers of a first nip at the folder station and into a first fold chute. The first fold chute cooperates with the rollers of the first nip to send the sheets through the rollers of a second nip and simultaneously produce a first fold in the sheet. The rollers of the second nip propel the partially folded sheet to a second fold chute. While the sheet is at the second fold chute, the rollers of a third nip grip the sheet and send it through the third nip, which produces a second fold. From the third nip, the fully folded sheet is propelled further in the downstream direction. In addition to producing the second fold in the sheet, the rollers of the third nip also partially activate strips of pressure sensitive adhesive on the sheet so as to loosely seal the sheet to itself.
While the trailing portion of the fully folded and partially sealed sheet is still gripped in the third nip of the folder station, the sheet leading portion is received in a nip at a sealer station. The rollers of the sealer station nip complete activation of the pressure sensitive adhesive, such that the sheet becomes fully sealed. The rollers of the seal nip propel the sheet out of the combination folder and sealer machine as a completed business form. Because the folded and partially sealed sheet is received at the sealer station before it is completely released from the folder station, the sheet is under complete control by the machine at all times. Consequently, the sheets do not become skewed as they are propelled from the folder station to the sealer station. Further, the fact that the sealer station is so close to the folder station considerably decreases the size of the combination folder and sealer machine compared with prior functionally equivalent equipment.
It is a feature of the invention that the rollers of the sealer station nip are biased away from each other, while the rollers of the folder station nips are biased toward each other. The sealer station rollers are adjustably set to a fixed clearance that suits a particular sheet and the strips of pressure sensitive adhesive applied to the sheet. Springs bias the sealing rollers away from each other to maintain the clearance. Because the sealer station rollers never touch each other, they do not wear on each other nor do they produce heat. Further, their operation is quieter than other pressure sealing machines.
Further in accordance with the present invention, the rollers at the folder station are mounted in the machine frame by a mounting system that renders the folding rollers exceptionally easy to remove and replace. Further, the folding roller mountings are designed to bias the folding rollers toward each other in a controllable manner.
The folding roller mounting system comprises two spacer plates that are mounted to opposite side walls of the machine frame. Each spacer plate has holes that are partially aligned with openings in the frame side walls associated with the respective folding rollers. The roller core ends are supported in bearing plates that are secured to the spacer plates. To remove a selected roller, it is necessary only to remove a spacer plate from one of the frame side walls. The selected roller is pulled from one end through the associated opening in the frame side wall. Simultaneously, the opposite end of the roller is pulled from the bearing plate at the other frame side wall. In that manner, the selected roller is removed from the machine without removing the other rollers and without affecting the machine side walls.
The method and apparatus of the invention, using easily replaceable folding rollers at a folder station that grip a folded sheet simultaneously with a sealer station, thus considerably reduces the size and weight of the combination folder and sealer machine as compared with prior equipment. The probability that a sheet will become skewed during the folding and sealing process is very low, even though the machine operates continuously at high speed.
Other advantages, benefits, and features of the present invention will become apparent to those skilled in the art upon reading the detailed description of the invention.